Michael Johns, Carly Smithson to duet on Wednesday night

Michael Johns and Carly Smithson will perform a duet tomorrow night during the first results-show telecast of American Idol's season 8 semifinals, Johns confirmed exclusively to EW.com. The pair, who only got the invitation to sing on Sunday, are still in talks with executive producer Ken Warwick about which number they'll perform.

Johns and Smithson, who finished eighth and sixth, respectively, on season 7 of Idol, had expected to appear this year during the "Hollywood Week" episodes, where they had served as ''Idol boot-camp'' mentors for the current crop of hopefuls; that footage, however, wound up on the editing-room floor. "Ken [Warwick] felt bad about it," explained Johns, and thus, the duet plans were hatched.

Johns said laughingly that he's "just a little" nervous to be taking to the Idol stage and appearing in front of the judges, but is excited by the fact that he'll be able to plug his upcoming debut album, which is slated for an April release, in front of 25 million viewers.

"The thing about Idol is, if you're respectful of it, and you enjoy it, and you're a good ambassador for the show, you're in it for life," says Johns, who made an appearance last Thursday along with Smithson and dozens of other former contestants at the launch of the "American Idol Experience" at Walt Disney World in Orlando, FL.

I was reading about this at EW.com. I'd sure like to hear the duet. I'll bet it will sound great as I like Micaels Johns.